Good Nutrition Essential for Astronauts

We are currently developing methods to assess nutritional status. These methods will be important for keeping the astronauts healthy during long space missions, like those planned for the International Space Station. Good nutrition is essential for everyone, especially when the astronauts spend a long time in weightlessness (zero gravity).

We have just completed a study with the Advanced Life Support group (ALS). This was part of the 90-day Phase III Chamber study, which ended in December 1997. Earlier last year we participated in a 60-day Phase IIa Chamber study with the ALS group. During these 2 studies, 4 crew members were confined to a chamber, for a specified number of days without leaving (see http://pet.jsc.nasa.gov). The air and water were recycled, and food and everything else needed were provided to the crew members inside the chamber, where they performed their daily activities. We did several things during Phase IIa and Phase III. One part of our project was a nutritional status assessment profile, a series of tests planned for use on the astronauts before, during, and after long-term space flight. These tests were used before and after the 60-day study, and before, during and after the 90-day study. It was a nice tie-in with our work in the NASA/Mir program, and we were able to test out the assessment profile.

The other part of our project was the use of a food frequency questionnaire, developed by Dr. Gladys Block of UC-Berkeley, designed for use on the Mir space station and tested during the ALS Chamber study. On the Mir, the questionnaire is filled out once a week, listing how much of the different types of foods are eaten. This information is down-linked to the ground, and once that information comes back to my group, we analyze the results to see if the person is getting enough calories and water. We then report these findings and any recommendations to the flight surgeon. We used a paper questionnaire for the Chamber studies, but the Mir astronauts complete their questionnaires via computer.

Dr. David Wolf is the first U.S. astronaut to participate in the nutritional status assessment studies. We did two sets of tests on him before he went to the Mir. On the Mir, he completed the questionnaire weekly, taking measurements of his body mass, and collecting samples which will be analyzed on his return to Earth. Once he returns home, we will repeat our earlier tests - taking blood and urine samples to determine his nutritional status after spending about four months in space. It is going to be really exciting for us when he returns. I'm sure he will be able to give us lots of feedback about the questionnaire, as this was the first time it was actually used in flight. It is important to consider not only the science aspects (the analysis of the data collected) but also its mechanics (ease in filling it out, the format, and how it works).

U.S. astronaut, Andy Thomas, who left on flight STS-89 (which launched January 22, 1998) to switch places with Dave Wolf on the Mir, will be the second astronaut to participate in these tests for us. We did preliminary tests on him six months before launch and again 10 days before launch. He will also do the questionnaire, and collect urine samples during the mission.

Nutrition is important for maintaining crew health before, during, and after long term space flight. Our nutritional status assessment profile will evaluate crew members' vitamin and mineral status, body composition, antioxidant, protein and bone health. We need to make sure that our astronauts are eating enough food, as this is critical for keeping them healthy. Data from previous missions show that they lose weight, including muscle, during space flight. Because of this we pay close attention to the amount of calories and protein they eat. Space flight also results in bone loss and increased loss of calcium in the urine, which could increase the risk for developing kidney stones. Water intake is needed for keeping the astronauts hydrated, and adequate intakes of vitamins and minerals are also important. As you can see, being in good nutritional balance is very important.

I am very excited about my work because, not only are we involved in keeping our astronauts healthy, but we are also generating a knowledge base of what happens to the body in long term space flight. Some of what we learn may have implications for science and research on Earth. Not since Skylab have we had the opportunity to have detailed nutritional data on man during long term space flight. I am one of the nutritionists on our team, which also includes a chemist, medical technologists, and a registered dietitian. Every member of the team has an important contribution to make in furthering our understanding of "nutrition in space".